National Morbillivirus Referral Laboratory, Division of Virology, IVRI, Mukteswar, Mukteswar-263138, India.
PPR virus has been classified under the genus Morbillivirus within the family Paramyxoviridae having single stranded negative sense RNA as genome. Other members of this genus are Rinderpest virus (RPV), canine distemper virus (CDV), measles virus (MV), phocid distemper virus (PDV) and Mobillivirus of porpoise and dolphins. PPR was first reported in sheep and goats at the Ivory Coast of West Africa. Since then, it was thought to be localized mainly in West and Central Africa. Later it has been reported from Arabian Peninsula, in the Middle East and in India. Recently, the disease has been reported from Bangladesh, Pakistan, Nepal, Israel and Saudi Arabia.
Serum samples are usually important material for serourveillance. With regard to Rinderpest and PPR, seromonitoring data has a very important role in establishing the extent of infection and also the protective immune response. An animal is most often considered to be protected, if the titer of virus neutralizing antibodies is high. Evidence of neutralization is an attribute of serum that is most often accepted as conclusive for an overall protction against a virus, with a few notable exceptions viz, Equine infectious anemia, Dengue, HIV etc. However in this study we compared nearly 368 field serum samples from goats for their antigenicity and antibody profile with respect to PPR. Most of the serum samples were positive with regard to both antigen and antibody (65%). Some serum samples were seen to be positive for antigen but negative for antibodies (27%). A few serum samples were negative for antigen and positive for antibodies (8%) Detection of antigen in serum could possibly suggest the presence of immune complexes (IC's). The nature of these IC's on the seroconversion and neutralization status of the animal is discussed in this paper.
